themes-wordpress/quadrat/sass/blocks/_query.scss

.wp-block-query-loop,
.wp-block-query {
	.wp-block-post-title {
		font-size: var(--wp--custom--heading--h3--font-size);
	}

	// Important is necessary to override any other font size rules applied to the exerpt.
	.wp-block-post-excerpt__more-text {
		font-size: var(--wp--preset--font-size--tiny) !important;
	}
}